The bioavailability (true digestibility) of three essential amino acids viz., lysine (Lys), methionine (Met) and tryptophan (Trp) in Indian fish meals and the role of caecal microflora on the bioavailability (BA) were studied using ten samples of fish meal collected from various sources across the country. These were precision-fed to intact or caecectomized roosters, separately. There were no significant differences in bioavailability of nitrogen and three amino acids between intact and operated birds in the samples. The caecectomy had no influence on the bioavailability of nitrogen, Lys, Met and Trp. The results were utilized in developing regression equations (n=30) to measure the bioavailability of three amino acids from the bioavailability of nitrogen (N). From among the equations those with highest accuracy (R2 = 0.85, 0.81 and 0.68 for Lys, Met and Trp, respectively) were: Lysine BA (%) = - 39.99 + 1.39 X NBA, Methionine BA (%) = - 50.52 + 1.52 X NBA, and Tryptophan BA (%) = - 83.60 + 1.81 X N BA.
Fish meal, bioavailability, caecectomy, amino acid, regression equation, nitrogen, lysine, methionine and tryptophan
